Starting means for internal combustion engines



Jan. 3, 1939. E, v. RIPPINGILLE 2,142,210

STARTING MEANS FOR INTERNAL QOMBUSTION ENGINES Fild May 22, 1957 1.9 "pacify L I 3mm Patented J an. 3, 1939 UNITED STATES STARTING MEANS FOR INTERNAL COIMBUS- TION ENGINES Edward V. Rippingille, Detroit, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application May 22,

6 Claims.

This invention relates to internal combustion engines, and particularly to Diesel engines.

More specifically it is concerned with means for heating the intake air of Diesel engines to facili- 5 tate starting.

The ignition of the fuel oil in Diesel engines is,

of course effected by the heat of compression of the air charge and this depends on the compression ratio and the initial air temperature. If the 10 initial air'temperature is below a certain mini mum, it is obvious that with a given compression ratio, the heat of compression will not reach the temperature at which spontaneous ignition will occur.

In practice the compression ratio selected for a given engine is governed by many practical considerations and it is often the case that while the compression ratio selected is sufficient to ignite the fuel under normal operating temperature conditions, it may be insufilcient to ignite the fuel when the engine is cold as at starting, particularly when the ambient air has a low temperature.

In such circumstances, a great quantity of the heat imparted to the air during the compression stroke of the engine is dissipated by radiation to the cold metal of the cylinders and pistons.

One object of the invention is a means of preheating the air in an air supply chamber having a volume several times that of the engine displacementand suificient to .provide several charges for the engine cylinders.

Another object of the invention is to associate air preheating means with an electric motor starting means and an electric accumulator providing current for both the air preheating means and the starting means, in such a way that the air heating means is not in circuit when the starting means is in circuit and vice versa, to reduce the maximum drain on the source of current pp y.

A still further object of the invention is to provide automatic means for breaking the electric heating circuit and switching on the starting means when the air in the supply chamber reaches a desired temperature.

The above and other objects of the invention will be apparent as the description proceeds.

The drawing shows the application of the invention to a two-cycle Diesel engine having piston controlled inlet ports in the cylinder walls and exhaust valves in the cylinder head. The ports in the cylinder walls supply air to the engine cylinders from an air chamber common to all the cylinders and to which air under pressure is sup- 1937, Serial No. 144,113

plied by the engine blower when the engine is running.

In the drawing:

Fig. 1 is a transverse sectional view of a part of a two-cycle Diesel engine to which the invention has been applied.

Fig. 2 is a wiring diagram of the electric circuit from a battery to the heating coils, to the control circuit for the starting motor, and to the starting motor.

Referring now to Fig. 1, the engine frame I encloses the cylinder 2, which is provided with inlet ports 3, controlled by the piston 4, which has a connecting rod to the engine crankshaft 6.

The cylinder head 8 is provided with exhaust valves 9, and supports the cylinder 2 in aligned bores through webs [0, H and i2, dividing the engine frame into compartments.

The space between the webs II] and H consti tutes an air chamber I4, from which the ports 3 open into the engine cylinder, when the piston is towards the end of its power stroke.

Air under pressure is supplied to the chamber I4 by a blower I5 having inlet and delivery ports l6 and I1, respectively.

The blower l5 may be driven in any suitable way from the engine crankshaft 6.

Each cylinder is provided with its own integral water cooling jacket 18. The space between the webs H and I2 of the engine frame constitutes a water chamber l9 from which water is supplied to the cylinder water jacket [8 through the ports 20. Water cooling spaces 2| in the cylinder head 8 are connected to the cylinder water jacket ill by the port 22.

The chambers l4 and i8 are sealed against leakage where the cylinder 2 passes through the webs 10, II and I2, by sealing rings 24, 25 and 26 of rubber or other suitable material.

Within the air chamber l4, heating coils such as 28 are provided to heat the air in the chamber H electrically by current from any suitable source, which may be a battery as shown at 36 in Fig. 2.

As shown in Fig. 1, the heating coils 28 are mounted on insulated supports 30, on the housing 3| of the blower l5 opposite the delivery ports ll thereof, and on insulated supports 32 on the cover plate or inspection door 33.

A terminal post 34 on the external side of the cover plate 33 is provided, and the heating coils may be connected together in series or parallel as may be desired.

The engine is cranked for starting by a conventional electric starting motor (not shown). I

The connections between the heating coils, the starting motor and the source of current supply are preferably as shown in Fig. 2.

Referring now particularly to Fig. 2, in which a battery 36 is shown as the source of current supply, the heating coil circuit is as follows: The positive pole of the battery is connected to a main switch 31 by a lead 38. From the main switch 37 a lead 39 is connected to a spring switch having a contact piece ii cooperating with a terminal 62. The switch 38 tends to be open, but

at lower temperatures is held closed by a bimetallic strip or other suitable temperature responsive device 53, which bears on the spring switch 30 through the insulating pad 86 thereon. From the terminalll2 there is a lead 35 to the heating coils 28. The circuit is completed by a lead 46 from the heating coils to the negative pole of the battery.

The starting motor control circuit is as follows: A solenoid l? controlling a switch 18 in a power lead 39 to the starting motor (not shown), is connected to the positive pole of the battery through the main switch 3'7. When the solenoid All is energized the switch 58 is closed. From the solenoid 3? is a lead 50 to a terminal 5|. The temperature responsive device 53 is provided with a contact piece 52. At higher temperatures, the device 43 moves towards the terminal 5| to close the connection 5t, 52, and this movement of the device 63 is followed by the spring switch 60, which breaks the connection QI, Q2. From the contact piece 52, there is a lead 53 to the negative pole of the battery 36.

The temperature responsive device J33 is installed in any suitable position in the air chamber Id of the engine, and is proportioned with the characteristics required automatically to break the heating coil circuit at Al, 52, and close the starting motor control circuit at 5!, 52, when if the temperature of the air is insumcient to cause the temperature responsive device to break the heating coil circuit at M, 42; that the temperature responsive switch is an automatic change-over switch precluding the possibility of energizing the heating circuit and the starting motor circuit at the same time, and that all the circuits are broken when the main switch 31 is open.

While the invention is peculiarly applicable to a two-cycle Diesel engine, it will be appreciated that it may be usefully applied to other types of engine in which heat may be required to facilitate starting.

While a low voltage battery has been shown in the drawing as the source of current supply for both the heating coils and the starting motor, it will be appreciated that the invention is not limited to the use of a battery for either of these purposes nor to the use of the specific circuit and automatic change-over means illustrated. Current for the heating coils may, for example, be taken from the public supply means or any other suitable source of supply irrespective of the voltage, and the change over from the heating to the starting means may be either manually or automatically effected as may be desired within the ambit of the invention.

I claim:

1. In an internal combustion engine in combination, air inlet ports, an air chamber communicating with the inlet ports, a heater for preheating the air in the air chamber before the engine is started, a starting motor and control means therefor responsive to the temperature of the air in the air chamber, whereby the engine is automatically cranked and started when the air in the air chamber reaches a certain temperature.

. 2. In an internal combustion engine in combination, air inlet ports, an air chamber communicating with the inlet ports, an electric heater for heating the air in the air chamber, an electric motor for cranking and starting the engine, a source of electric current supply for the heater and the motor, a solenoid controlled switch for the starting motor, a main switch in the solenoid circuit and the heater circuit and a temperature responsive switch automatically to close the heater circuit when the air in the air chamber is below a certain temperature and to close the solenoid circuit when the air in the air chamber reaches the said temperature, whereby, upon closure of the main switch, and if the temperature of the air in the air chamber is sufficiently high, the engine will be cranked by the starting motor; alternatively if the temperature of the air in the air chamber is not sufiiciently high it will first be heated to the required degree before the engine is cranked by the starting motor.

3. The combination according to claim 2 in which the engine is a two-cycle engine provided with a blower and the air chamber forms part of an air supply duct between the blower and the engine.

4. The combination according to claim 2, in which the temperature responsive switch automatically opens the heater circuit as it closes the solenoid circuit.

5. The combination according to claim 2, in which the temperature responsive switch automatically opens the heater circuit as it closes the solenoid circuit, and the air chamber has a volume greater than the displacement of the engine, whereby air sufficient for at least one full charge for each cylinder of the engine may be heated before the engine is started; said air being admitted to each cylinder of the engine as the engine is cranked by the starting motor after the heater has been switched ofi.

6. In an internal combustion engine, in combination, air inlet ports, an air chamber communicating with the inlet ports, an electric heater for heating the air in the air chamber, an electric motor for cranking and starting the engine, a battery, a circuit for the supply of current to the heater, a power circuit for the starting motor, a switch in the power circuit, means for closing the switch in response to the flow of current in a control circuit therefor, a main switch in a conductor common to the heater circuit and the control circuit, and a temperature responsive change-over switch device to close the heater circuit and open the control circuit when the air in the air chamber is below a certain temperature, and to open the heater circuit and close the control circuit when the air in the air chamber reaches the said temperature.

EDWARD V. RIPPINGILLE. 

